We’ve seen this hardware used in a similar way before. Because each ‘bulb’ has its own microcontroller, color data is shifted in via a serial bus. Orient the modules in any pattern you choose and account for that layout in software.

Since the strings have 50 bulbs, [John] simply cut off the one on the end to form his 7×7 matrix with the remaining 49 units. A square of plywood with a grid of holes holds each in place. Cord mess is not a problem as the extra was cut out and the remainders were soldered together again. [John] uses an Arduino Pro to feed in the data, which you can see for yourself in the clip after the break.

All these different serial-controlled LEDs make me wonder: why is there still not a RGB LED with a i2c or spi controller chip built-in? There are blinking LEDs and color-fade LEDS indicating that putting a chip in a LED is easy. why not make a pre-packaged 4-pin LED: Vcc, GND, SCL, SDA? It would allow so meny cool things to be done in a small space. [ the main problem with current modules is that they are all too big ]